P0401 Code - EGR Valve/Ports/Check Engine Light?

An Acura RL 3.5L 6cycl 1997

[i] Code due to Insufficient flow - Is there away of differentiating whether the problem is due to a faulty EGR valve or just dirty ports; (i.e. a way of testing the EGR valve)

[ii] Are there special tools for cleaning these ports ? Seen kits advertised, but dealers do not carry them in their arsenal of parts!

[iii] After cleaning ports and replacing EGR valve if needed does the “Check Engine” light turn off automatically or is there a resetting to be done.


If you are not subject to emissions testing, you can ignore this one… You can reset the CEL by disconnecting your negative battery cable for a minute or two…

If passing an emissions test is part of your life, then cleaning or replacing the exhaust gas passages will be necessary…

Subject to emission testing in a few days